1. Field of the Invention
The invention relates to a manufacturing method of a film carrier tape for a TAB (Tape Automated Bonding) technology, and more particularly to a manufacturing method of a film carrier tape which is produced with high productivity and readily under quality controls.
The invention also relates to a film carrier tape to be used for the TAB technology.
2. Description of the Related Art
The TAB technology mounts electronic parts such as semiconductor devices on a long insulating film, which is called a film carrier tape and has a number of wiring patterns formed, by bumps or the like. A package having the semiconductor devices mounted on the film carrier tape is designated as the film carrier package or tape carrier package.
With high integration of the semiconductor device in these years, the size and arrayed pitch of the connection terminals of the semiconductor devices have become fine even further. Accordingly, the film carrier tape on which such semiconductor devices are mounted is also becoming small.
FIG. 5 is a flowchart describing a general manufacturing process of a film carrier tape.
First, a tape-shaped conductive foil such as a copper foil is laminated onto a tape of insulating resin such as polyimide, which has carrying guide holes (sprocket holes) and device holes formed by punching or the like, with an adhesive layer therebetween, and the laminated film is pressed by being passed through rollers into an integrally bonded form.
Then, a resist is applied onto the conductive foil, exposed and developed to etch the exposed portion with a predetermined wiring being covered, thereby forming a wiring pattern. And, the wiring pattern is plated.
Appearance, size and properties are examined, resulting in completing a film carrier tape on which a number of wiring patterns are formed in its longitudinal direction.
As described above, with the high integration of the semiconductor device in these years, the wiring pattern of the film carrier tape has also become fine still further. In the wiring pattern, a mounting pitch of a part, which is called an inner lead, to be connected to the connection terminal of the semiconductor device is made very small. For example, the mounting pitch has become smaller gradually from 100 .mu.m to 80 .mu.m, and to 60 .mu.m.
To improve reliability and productivity of the film carrier package, therefore, it is significant to improve the relative precision between the wiring pattern (especially, the inner lead) and the connection terminal of the semiconductor device. But, it is very hard to achieve satisfactory precision in actuality.
To provide a high-precision film carrier tape, it was conventionally practiced, for example, to control the thickness of an adhesive layer used to adhere a base film and a conductive foil and to monitor the quality of the wiring pattern (lead group) formed by etching. But, such measures were still not enough to produce a film carrier tape having satisfactory precision.
FIG. 6A is a plan view schematically showing the wiring of a film carrier tape in a portion corresponding to a single unit of the wiring. It is seen that a device hole is displaced from its proper location. FIG. 6B is a schematic view showing that inner leads of a conductor wiring were formed as being displaced from the appropriate location.
This film carrier tape is formed of, for example, a base film 91 made of an insulating resin such as polyimide and a wiring 92w formed on the base film 91. Sprocket holes 91s are formed as carrier guide holes on both sides of the base film 91 of the film carrier tape. And, on the base film 91, a device hole 91h is formed as a region where an electronic part such as a semiconductor device or the like is mounted. The wiring 92w is formed by patterning, for example, a conductive foil such as a copper foil, which is laminated with the base film 91, by a photoetching process or the like. And, the wiring has inner leads 92i which are protruded into the device hole, and to mount the semiconductor device on the film carrier tape, the inner leads are connected with connection terminals (not shown) of the semiconductor device. As described above, with the high integration of the semiconductor device, the size and forming pitch of the connection terminals of the semiconductor device are becoming fine even further. As a result, the inner leads 92i of the film carrier tape are also required to be made with high precision.
However, there were disadvantages that the device hole 91h is deformed in shape, the inner leads 92i of the wiring are displaced from the proper location and the like (FIG. 6B).
As described above, the film carrier tape, on which electronic parts such as a highly integrated semiconductor device having the connection terminals with a very fine size and mounting pitch are mounted, has disadvantages that it is hard to produce and poor in productivity. Thus, the conventional film carrier tape and method of manufacturing the same have disadvantages in providing a highly reliable film carrier package with high productivity.